.app {

}

.app h1,
.app h2 {
    text-align: center;
}

.board {
    width: 240px;
    margin: 0 auto;
    border-right: 1px solid #888;
    border-bottom: 1px solid #888;
    display: flex;
    flex-wrap: wrap;
}

.board .square {
    width: 80px;
    height: 80px;
    border: none;
    border-top: 1px solid #888;
    border-left: 1px solid #888;
    text-align: center;
    line-height: 80px;
    font-size: 40px;
    font-weight: bold;
    padding: 0;
}

.board .square.red {
    background-color: #f00;
    color: #fff;
}

